I have a device that uses an old DLP-USB 232M device from FTDI.I have tried installing it in my system. It used to work on win XP but after upgrade to win 7, it has refused to function

From what the manufactures said, its supposed to be able to work with the new upgrade driver files, but each installation , there is no result. I am supposed to have "USB serial converter" among my devices and the port should be "USB Serial port"